CN102509159A - Electrical-information-acquisition-system-based theoretical line loss estimation method for distribution network - Google Patents

Abstract

The invention discloses an electrical-information-acquisition-system-based theoretical line loss estimation method for a distribution network, and aims to overcome the shortcomings of great errors of the conventional theoretical line loss estimation method for the distribution network, difficulty in accurate analysis on the characteristics of load fluctuation, unbalance, harmonic distortion, parameter variation and the like of the distribution network, and the like. By the method, each loss influencing factor of a medium and low voltage distribution network can be scientifically, perfectly and comprehensively reflected; and compared with a 'root-mean-square current method', an 'average current method', a 'maximum current method', an 'equivalent resistance method' and the like for estimating line loss only according to the single line diagram of the distribution network, typical day 24 hours, asynchronous current recording data and the like in DL686-1999 guide of calculation of grid energy loss, the invention has more accurate algorithms, parameters, load data and the like for the theoretical line loss, and provides a novel concept and a novel method for the loss analysis and energy efficiency evaluation of the distribution network.

Description

Power distribution network theory wire loss appraisal procedure based on the power information acquisition system

Technical field

The present invention is the basis with the accurate metric data of periodicity of power information acquisition system " all standing, the full collection ", relates to system for distribution network of power theory wire loss computing field, is specifically related to the power distribution network theory wire loss appraisal procedure based on the power information acquisition system.

Background technology

Power distribution network line loss Theoretical Calculation is actual load and the normal operating mode according to power distribution network, calculates the actual active power loss and the energy loss in the certain hour section of each element in the power distribution network.Calculate the economy that to identify the distribution net work structure and the method for operation through theory wire loss; Find out excessive element and the reason thereof of loss in the electrical network; Examine actual line loss whether true, accurately, rationally and the difference of actual line loss rate and technology (theory) line loss per unit; Confirm the degree of unexplained loss, the present situation of clear and definite power distribution network operational management.According to the formation of technological line loss, i.e. the shared proportion of shared proportion, variable loss and the constant loss of line loss and transformer loss, can find power distribution network weak link, confirm that the main direction of damage falls in technology so that adopt an effective measure, reduce line loss.It is planning and design and formulation year, season, month line loss plan target and the theoretical foundation of falling the damage measure that the line loss of power distribution network is calculated.Recommend to have medium voltage distribution network to adopt rms current method, average current method and substitutional resistance method according to " DLT 686-1999 power network line losses calculates guide rule " is main; The electric energy loss of elements such as circuit, Transformer Winding, current-limiting reactor should be calculated by the daily load curve of element.The low-voltage network network is complicated, load skewness weighing apparatus, and data is incomplete, generally adopts simple method to calculate, and recommends with platform district proportion of goods damageds method and voltage loss rate method.

The loss appraisal procedure of circuit generally is the static parameter, cross-sectional area, length etc. of lead, utilizes operational factors such as typical case's day electric current, power, and account temperature, part throttle characteristics are calculated typical case's day loss, and then the line loss of calculating month.

1. rms current method

The rms current method is the basic evaluation method.The physical concept of rms current method is that the electric energy loss of flowing through in the circuit that rms current produced is equivalent to the interior at one time electric energy loss that is produced of actual load.The advantage of rms current method is: method is simple; Go out rms current according to data computation such as representing days 24 hours integral point load currents or active power, reactive power or meritorious electric weight, capacity of idle power, voltage, substation transformer rated capacity, parameter and just can carry out electric energy loss calculating, be easy to computer programming calculation.Shortcoming is: represent day to choose difference and have different results, the error of calculation is bigger.

The resistance of certain element is R (Ω) in the establishing electrical network, and the current effective value through this element is I (A), and then the energy loss Δ A in this element 24h is calculated as follows:

$\mathrm{\ΔA}=3*{10}^{-3}\underset{0}{\overset{24}{\∫}}{I}^2\mathrm{Rdt}$

Because the analytical expression I=f (t) of load curve is difficult for obtaining, and makes above-mentioned integration type find the solution difficulty.General through this element being represented day actual measurement of 24h load current, draw the stepped appearance load curve, approximate think each hour internal loading be constant, therefore can carry out line loss to the following formula segmentation by the hour and calculate.I _iRepresent day 24h current value that obtains of load measurement on schedule, then following formula can be expressed as:

$\mathrm{\ΔA}=3*{10}^{-3}*(I_1^2+I_2^2+...+I_{24}^2)R=3*{10}^{-3}*I_{\mathrm{eff}}^2*R*24$

The average daily side's electric current of define and represent:

$I_{\mathrm{eff}}=\sqrt{\frac{I_1^2+I_2^2+....+I_{24}^2}{24}}=\sqrt{\frac{\underset{t=1}{\overset{24}{\mathrm{\Σ}}}\frac{P_t^2+Q_t^2}{U_t^2}}{24\×3}}$

In the formula:

P _t-represent day 24h three phases active power that obtains of load measurement on schedule;

Q _t-represent day 24h three phase reactive power that obtains of load measurement on schedule;

U _t-with P _t, Q _tThe line voltage of same same time of measurement point end.

The total losses of power distribution network equal the loss sum on the whole elements that will consider.Represent the total losses electric weight of day the whole network to gather, can and represent a day power supply ability according to the power supply whole month then, convert out loss electric energy and the line loss per unit of the whole month by open circuit loss and the classification of load loss two parts.

2. average current method

The average current method is also claimed the shape coefficient method, is to utilize the equivalent relation of rms current method and average current to carry out electric energy loss calculating, is derived from by the rms current method.The physical concept of average current method is that the electric energy loss of flowing through in the circuit that average current produced is equivalent to the interior at one time electric energy loss that is produced of actual load.The advantage of average current method is: be easier in the reality to obtain and comparatively accurate electric weight as calculating parameter, result of calculation is comparatively accurate, the electric energy loss that calculates precision as a result is higher; Just can carry out electric energy loss according to per day electric current of representative and data computation such as calculating shape coefficient and calculate, be easy to computer programming calculation.Shortcoming is: to there not being the substation transformer of actual observation record, shape coefficient is difficult for confirming that the error of calculation is bigger.

The definition shape coefficient

Then obtain by root mean square method formula

Or

A _a, A _rFor representing meritorious, the reactive energy of day.

The rate of load condensate of definition load curve $f=\frac{I_{\mathrm{Av}}}{I_{\mathrm{Max}}}$ And ratio of minimum load to maximum load $\mathrm{\β}=\frac{I_{\mathrm{Min}}}{I_{\mathrm{Max}}},$ When f>=0.5, $K^2=\frac{\mathrm{\β}+\frac{1}{3}{(1-\mathrm{\β})}^2}{{\left(\frac{1+\mathrm{\β}}{2}\right)}^2};$ F＜0.5 o'clock, $K^2=\frac{f(1+\mathrm{\β})-\mathrm{\β}}{f^2}.$

The method be otherwise known as average current method, i.e. shape coefficient method.

3. maximum current method

The maximum current method is also claimed the loss factor method, is to utilize the equivalent relation of rms current method and maximum current to carry out electric energy loss calculating, is derived from by the rms current method.The physical concept of maximum current method is that the electric energy loss of flowing through in the circuit that maximum current produced is equivalent to the interior at one time electric energy loss that is produced of actual load.The advantage of maximum current method is: the data that calculating needs is few, only need measure and represent day maximum current and data such as calculating loss factor just can carry out electric energy loss calculating, is easy to computer programming calculation.Shortcoming is: loss factor is difficult for calculating, different load curves, network structure and part throttle characteristics, and the loss factor that calculates is different, can not be general, must be when using the method according to electrical network actual conditions computed losses factor; Computational accuracy is low, is usually used in the less demanding situation of computational accuracy.

With the average current method, the definition loss factor $F=\frac{I_{\mathrm{Eff}}^2}{I_{\mathrm{Av}}^2},$ So $\mathrm{\Δ\; A}=3*I_{\mathrm{Max}}^2*F*R*T*{10}^{-3},$ The method is called maximum current method (loss factor method).

4. substitutional resistance method

Substitutional resistance method ultimate principle does; Suppose that certain low-voltage circuit is made up of some branch lines; Total load electric current through the collection of circuit head end is that certain value is calculated the substitutional resistance on road completely, replaces complicated circuit, and complicated circuit is oversimplified; Make the more directly perceived and standard of expression of line loss calculating formula, help line loss analyzing.The advantage of substitutional resistance method is: fairly perfect in theory, on method, overcome the infull present situation of power distribution network data acquisition; Need not collect each load point service data, only relevant with structural parameters substation transformer rated capacity, sectionalized line resistance, calculate the substitutional resistance data and just can carry out electric energy loss and calculate.Shortcoming is: need the hypothesis design conditions, influence computational solution precision; To not surveying the substation transformer of load record, suppose that load distributes by proportional with the substation transformer rated capacity, each node load rate is identical, and this calculating is not in full conformity with the actual load situation; Suppose that each load point power factor, shape coefficient are identical with voltage, but generally speaking, the power factor of each load point of real system, loading coefficient and working voltage are all inequality, the electric energy loss value error that calculates is bigger.

Because the medium voltage distribution network node is many, branch line is many, and each element do not possess the condition of surveying the record service data, makes its line loss calculate much complicated than high voltage distribution network.Therefore, should make every effort to simply, can satisfy the order of accuarcy of real work needs simultaneously again, distribution ridge line loss calculated had feasibility for the line loss appraisal procedure of this power distribution network.Each load bus of power distribution network is unkitted electric energy meter and other table timing, can calculate by the condition that the rate of load condensate that is connected to each node substation transformer equates.

The basic thought of substitutional resistance method is the line loss of whole power distribution network to be regarded as by two parts form, and one of them part is the fixed loss that distribution transforming depressor iron core is produced.Another part is the variable loss that corresponding line and Transformer Winding produce.The former can think constant approx in the process of load variations, the latter then changes along with the variation of load.Calculate for simplifying, replace for two substitutional resistances under this part line loss power supply head end function of current that changes with load.One of them is the substitutional resistance of corresponding lead loss, and another is the substitutional resistance of corresponding whole public substation transformer winding losses.

The substitutional resistance of lead:

$R_{\mathrm{eqL}}=\frac{\underset{i=1}{\overset{m}{\mathrm{\Σ}}}(S_i^2*R_i)}{{\left(\mathrm{\Σ}{S}_a\right)}^2}$

Wherein: ∑ S _aBe the total volume of each node substation transformer of this circuit, S _iBe total volume through the substation transformer of i line segment power supply, the resistance of Ri i section lead.

The substitutional resistance of the winding of whole common transformers:

$R_{\mathrm{eqR}}=\frac{U^2\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\mathrm{\Δ}{P}_{\mathrm{kj}}}{{\left(\mathrm{\Σ}{S}_a\right)}^2}*{10}^3$

∑ S wherein _aBe the total volume of each node substation transformer of this circuit, Δ P _KjBe the power of the specified short circuit loss of the public substation transformer of j node, U is a substation transformer high-pressure side rated line voltage.

So whole power distribution network equivalent impedance is:

R _eq＝R _eqL+R _eqR

Distribution wire is represented the total losses electric weight of day so:

$\mathrm{\ΔA}=[\mathrm{\Σ\Δ}{P}_{0j}{\left(\frac{U_{\mathrm{av}}}{U_f}\right)}^2+3*K^2{I}_{\mathrm{av}\left(0\right)}^2*R_{\mathrm{eq}}*{10}^{-3}]*24$

In the formula:

U _fThe tap voltage of-transformer, kV;

U _Av-average voltage, kV.

The difference of the appraisal procedure that adopts causes the inconsistent and actual line loss value difference of result of calculation apart from bigger, and the analysis meeting of power distribution network saving energy and decreasing loss is produced certain mistaken ideas.Table 1 is summed up and is estimated for the existing theoretical loss appraisal procedure of power distribution network.

The existing theoretical loss appraisal procedure of table 1 power distribution network is summed up and is estimated

Summary of the invention

Low and medium voltage distribution network mainly contains following characteristics: 1. network structure is radial, network-intensive, and branch line and entrance line account for principal ingredient; 2. the line footpath is less, and line resistance is bigger; 3. the kind of loading is various, and power supply mode is complicated, does not have unified electric network composition, and three-phase load and single-phase load are also deposited, and the position disperses, and load changes bigger round the clock, and seasonality is arranged; 4. low loss of presenting a theatrical performance as the last item on a programme the district receives platform district power source voltage to influence bigger; 5. power distribution network measure monitor table meter disposes To be improved.

In influencing the three elements of line loss analyzing (model algorithm, line parameter circuit value, image data), power transmission network and low and medium voltage distribution network all have bigger difference.In fact three elements are complementary; Because each load bus of power transmission network is actually the bus of each electric pressure transformer station; Be not to be the real load that cut-offs, the simultaneity of being loaded effects, load curve is comparatively level and smooth; Regularity is also stronger, generally demonstrates early peak, evening (lamp) peak, night paddy, day equality curve characteristics; So; General so long as adopt day collection 24 point modes to calculate the loss characteristic that typical case's day loss just can reflect defeated net preferably; And because the power transmission network impedance ratio of voltage levels is bigger, and the three-phase equilibrium degree is higher; Adopting the single line power flow algorithm is to select preferably, is that convergence or consistance are all very high.

Table 2 low and medium voltage distribution network loss analysis key element and characteristic

Calculate an accuracy difficult problem for solving the power distribution network theory wire loss, take all factors into consideration multiple factor affecting such as three-phase imbalance, harmonic wave, the present invention has adopted following technical scheme:

1. based on the exact algorithm of the three-phase complete period integration loss of power information acquisition system

(1) medium voltage distribution network

Only on phase line, its value is the power attenuation of circuit in the phase three-wire three unbalanced system:

$\mathrm{\Δ}{P}_{\mathrm{unbalance}}=({I_a}^2+{I_b}^2+{I_c}^2)\·R$

Because medium voltage network gauging table meter is only gathered electrical quantitys such as

, then need calculate the electrical quantity of B phase according to small current neutral grounding system .

${\stackrel{\·}{I}}_B=-({\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_C)$

Wherein,

is respectively the angle of each this phase voltage of phase current hysteresis; If the value of

that phase three-wire three gauging table meter provides for providing with

line voltage standard then should be modified to

respectively

So line loss can be represented with following formula in the phase three-wire three unbalanced system:

$\mathrm{\Δ}{P}_{\mathrm{unbalance}}=({I_a}^2+{I_b}^2+{I_c}^2)\·R$

(2) substation transformer

Transformer loss is made up of variable loss and fixed loss two parts, and variable loss is approximately ohmic loss, changes with the variation of loading, and fixed loss it is generally acknowledged and immobilized.Because substation transformer generally adopts Δ/Y-11 mode of connection, because the load unbalanced while of each winding of low pressure has also caused high-pressure side zero-sequence current circulation I ₀Loss, its loss will become greatly, its theoretical value is:

$\mathrm{\Δ}{P}_{\mathrm{Tunbalance}}$

$=P_{\mathrm{kunbalance}}^{\′}+P_0^{\′}+{I_0}^2\·R_0$

$=({I_A}^2+{I_B}^2+{I_C}^2)\·R_k+P_0+{I_0}^2\·R_0$

$=({I_A}^2+{I_B}^2+{I_C}^2)\·\frac{P_k}{3{I_n}^2}+P_0+I_0^2\·R_0$

(3) the low district's power distribution network of presenting a theatrical performance as the last item on a programme

In the three-phase and four-line unbalanced system; Owing to superimposed current is arranged on the neutral line, when calculating the low voltage network line loss, need fully take into account the influence of three-phase imbalance to line loss; Because low-pressure system neutral-point solid ground; The zero-sequence current loss of the neutral line is very important, and since the neutral line adopt sometimes and the not collinear footpath of phase line, when analyzing in line resistance provide separately.Because the general single-phase gauging table meter of gathering this phase current of phase voltage

phase current

that adopts in the low-pressure system; Three-phase four gauging tables of threephase load are also only gathered the electrical quantity of three-phase, so neutral current

can obtain through computes:

${\stackrel{\·}{I}}_N={\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_B+{\stackrel{\·}{I}}_C$

Annotate: N phase current phase angulation is to be benchmark with the A phase voltage, lags behind to just, and is leading for negative.

Bring current in middle wire mould value into the loss formula, can get that the total loss of circuit is in the three-phase four wire system:

$\mathrm{\Δ}{P}_{\mathrm{unbalance}}$

$=({I_a}^2+{I_b}^2+{I_c}^2)\·R_p+{I_N}^2\·R_N$

2. Harmonic Distortion in Distribution System parameter correction

The harmonic electric energy of electrical network consumption is to be caused by wherein nonlinear-load.Because nonlinear-load itself is not produced electric energy, therefore, harmonic electric energy can only be to come from the conversion of nonlinear-load from the fundamental energy of power supply absorption.Therefore harmonic wave has caused the additional electric energy loss.When the high-frequency harmonic electric current flows through conductor, receive the influence of kelvin effect, conductor is increased the effective resistance of harmonic current, thereby increased the power loss and the electric energy loss of circuit, it will be more obvious that harmonic current pollutes the influence of line loss.

(1) distribution line

Concerning the harmonic impedance of overhead transmission line and cable line, more accurate method for expressing is to adopt distributed constant circuit.In the mesolow distribution system,, can think that the harmonic wave reactance of circuit is directly proportional with frequency because harmonic frequency often is not very high.Consider that circuit in the power distribution network is long, voltage is lower, so the line-to-ground admittance can be bribed suddenly and disregarded.

Conductor all has frequency characteristic, and under the different frequency function of current, the resistance of conductor is different, i.e. kelvin effect.Under harmonic condition, more obvious with the increase kelvin effect of frequency because kelvin effect reduces the useful area of lead, so bigger in the impedance of the condition line of harmonic wave, harmonic loss also increases thereupon.

Harmonic loss is the important component part of system's total losses, and the kelvin effect of harmonic current on lead reduces the net sectional area of lead, and resistance increases, and has aggravated the lead heating, and the lead loss is strengthened.

According to line resistance and circuit cross-section relation formula

Consider kelvin effect, definition δ _nThe degree of depth when measuring the 1/e that decays to face value for electromagnetic wave entering lead internal field is a skin depth:

${\mathrm{\δ}}_n=\sqrt{\frac{\mathrm{\ρ}}{\mathrm{\πnf\μ}}}$

So, substitution A=2 π b δ _n, the lead effective resistance computing formula that nth harmonic is corresponding is:

$R_n=\frac{\mathrm{\ρl}}{2\mathrm{\πb}{\mathrm{\δ}}_n}=\frac{\mathrm{\ρl}}{2\mathrm{\πb}\sqrt{\frac{\mathrm{\ρ}}{\mathrm{\πnf\μ}}}}=\frac{l}{2b}\sqrt{\frac{\mathrm{\ρnf\μ}}{\mathrm{\π}}}=\sqrt{n}{R}_1$

(2) substation transformer

Substation transformer harmonic wave resistance can be collinear the roadlock value analyze, the harmonic wave reactance can be similar to be thought and is directly proportional with system frequency.Thus, the nth harmonic impedance of transformer can be expressed as:

$Z_{\mathrm{Tn}}=\sqrt{n}{R}_{T1}+\mathrm{jn}{X}_{T1}$

(3) reactive power compensator

The harmonic impedance of reactive-load compensation capacitor device is by capacitor self capacitive reactance X in the distribution system _CAnd series inductance induction reactance X _CLTwo parts are formed.Consider its frequency effect separately, then can get:

Z _Cn＝jnX _CL-jX _C1/n＝jX _C1(n ²K-1)/n

In the formula: K-series reactance rate, K=X _CL/ X _C1

(4) load

Here said load is meant the load of removing beyond harmonic source and the parallel capacitive compensation equipment.During frequency characteristic, the direct harmonic impedance of calculated load.The impedance model of considering low and medium voltage distribution network actual load (illumination, power etc.) can equivalence be resistance sense series connection model: Z=R+jX.

Its harmonic impedance of power distribution network summation load does $Z_n=R+\mathrm{JX}=\sqrt{n}{R}_1+\mathrm{Jn}{X}_1.$

The beneficial effect of technical scheme of the present invention is:

Solve the power distribution network theory wire loss and calculated an accuracy difficult problem; Take all factors into consideration multiple factor affecting such as three-phase imbalance, harmonic wave; Solved the accurate Calculation of power distribution network theory wire loss; More approaching on-the-spot active loss situation, carrying out for the work of power distribution network saving energy and decreasing loss provides accurate computation model and technical support.

Overcoming the rms current method represents and chooses different different results, the deficiencies that the error of calculation is bigger of producing day.

Overcome the average current method to there not being the substation transformer of actual observation record, shape coefficient is difficult for confirming the deficiency that the error of calculation is bigger.

Overcome maximum current method loss factor and be difficult for to have calculated, different load curves, network structure and part throttle characteristics, the loss factor that calculates is different, can not be general, must be according to electrical network actual conditions computed losses factor when using the method; Computational accuracy is low, is usually used in the less demanding limitation such as situation of computational accuracy.

Method of the present invention can be according to the load data of real-time collection, calculates any one day, the loss situation of arbitrary lead, transformer, can realize that loss calculates in real time.

Method computation process of the present invention terminal load data and circuit, the transformer parameter corresponding loss of retrodicting of serving as reasons is calculated to the circuit head end always, and there is not the convergence problem in the computation process simple and fast.

Method of the present invention is the basis with the accurate metric data of periodicity of power information acquisition system " all standing, the full collection ", has guaranteed real-time, accuracy and the operability of low and medium voltage distribution network loss computational analysis.

Method of the present invention is difficult to the deficiency of Accurate Analysis to the load fluctuation of power distribution network, parameter variation etc., preferably resolves load fluctuation, parameter and changes losses of distribution network is calculated influence.

Method of the present invention is the basis with high-precision load image data, has considered that accurately factors such as three-phase imbalance, harmonic distortion influence losses of distribution network.

Method of the present invention has overcome maximum current method loss factor and has been difficult for calculating, different load curves, network structure and part throttle characteristics, and the loss factor that calculates is different, can not be general, must be when using the method according to electrical network actual conditions computed losses factor; Computational accuracy is low, is usually used in the less demanding limitation such as situation of computational accuracy.

Description of drawings

In order to make content of the present invention by clearer understanding; And be convenient to the description of embodiment, it is following to provide the description of drawings relevant with the present invention below: Fig. 1 is based on the exact algorithm of the three-phase complete period integration loss of power information acquisition system and introduces Background.Fig. 2 is the medium voltage distribution network topology diagram in the instance analysis of the present invention;

Fig. 3 is that the exact algorithm of the three-phase complete period integration loss based on the power information acquisition system of the present invention is introduced Background.

Embodiment

Fig. 1 is based on the exact algorithm of the three-phase complete period integration loss of power information acquisition system and introduces Background; Like figure; The present invention has assessed rms current method, average current method, maximum current method; Considered that power distribution network load fluctuation property is strong, the characteristics of three-phase imbalance, distortion, the three elements (model algorithm, line parameter circuit value, image data) of having studied line loss analyzing in medium-voltage distribution circuit, substation transformer, the low district's scope of presenting a theatrical performance as the last item on a programme have drawn the exact algorithm of three-phase complete period integration loss.

Fig. 2 is the instance analysis medium voltage distribution network topology diagram according to the inventive method, and this figure is one section typical low and medium voltage distribution network, and I section, II section, III section circuit and unit type, parameter are as shown in the figure, and the I section is a massive quantity power supply and measurement, and II Duan Weigao supplies low meter.According to of the present invention following based on practical implementation step based on the exact algorithm of the three-phase complete period integration loss of power information acquisition system:

1) draws low and medium voltage distribution network topology data

Following division is done on assessment border according to low and medium voltage distribution network.

(3) medium voltage distribution network

Medium voltage distribution network is pressed trunk and branched line promptly, and electric pressure is mainly 10kV, also comprises a spot of 6kV, 35kV and the new 20kV that adopts in some areas.

Topology information: circuit model (impedance), length, articulate distribution transforming, on-pole switch, non-full phase equipment (like single-phase change) separate; If in the test circuit of choosing and the station or the outer circuit in station " handle " arranged, when the back brake of contact, block switch on the post switches, should write down switching time and collection capacity information accordingly.

(4) substation transformer

Back ground Information: distribution transforming model and corresponding copper loss, iron loss, short-circuit voltage number percent, no-load current number percent, reactive compensation capacity configuration; Reactive-load compensation and cut humorous device

The relation and the calculating of damage value is invested and fallen to reactive power compensator: import the investment of reactive power compensator and fall the damage theoretical value, output investment rationality.

Harmonic treating apparatus investment and fall the relation and the calculating of damage value: the investment of input harmonics controlling device and fall the damage theoretical value, output investment rationality.

(5) the low district's power distribution network of presenting a theatrical performance as the last item on a programme

Low pressure three-phase four-wire system line topological information: circuit model (impedance), length, load point position and connect separate; Each low-voltage circuit should write down switching time and corresponding collection capacity information if any operation of phase inversion.

2) import the low and medium voltage distribution network load data

Middle load, the i.e. distribution transformer load of pressing: distribution transforming metering method (high meter of high pressure or height supply low meter), mutual inductor ratio, gauging table meter precision.The load metric data: collection period was at least 1 hour, typical case's day (during aestivating down with the wind, when low ebb is loaded etc.) require to be refined as 15 minutes; The electrical quantity of gathering comprises electric flux, electric power, voltage, electric current, power rate etc.

Low-voltage load: collection period is 1 hour, typical case's day typical low-voltage load point (during aestivating down with the wind, when low ebb is loaded etc.) be refined as 15 or 1 minutes; The low-voltage load point overwhelming majority is a single-phase load, only needs the single-phase electrical information of record to get final product, if but be multiphase load, like power facilities such as elevators, should write down the three-phase data.

Harmonic distortion: for the bigger load point of load distortion, import the each harmonic data,, can adopt power quality analyzer device measured data to import because general power information acquisition system does not comprise harmonic data.

3) the low and medium voltage distribution network loss is calculated

Employing is calculated based on the exact algorithm of the three-phase complete period integration loss of power information acquisition system.

A) medium voltage distribution network

Distribution transforming massive quantity power supply and measurement: (collection point is in the high-pressure side, and table is counted three-phase three-wire electric energy meter)

$\mathrm{\Δ}{P}_{\mathrm{unbalance}}=({I_a}^2+{I_b}^2+{I_c}^2)\·R$

B) the low district of presenting a theatrical performance as the last item on a programme:

Single-phase family table: (be without loss of generality as in the A phase)

$\mathrm{\Δ}{P}_a={I_a}^2\·R_a+{I_N}^2\·R_N=2{I_a}^2\·R_a$

The three-phase user:

$\mathrm{\Δ}{P}_{\mathrm{unbalance}}$

$=({I_a}^2+{I_b}^2+{I_c}^2)\·R_p+{I_N}^2\·R_N$

Wherein:

${\stackrel{\·}{I}}_N={\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_B+{\stackrel{\·}{I}}_C$

Instance analysis

The exact algorithm that the present invention will propose based on the three-phase complete period integration loss of power information acquisition system be applied in actual low and medium voltage distribution network loss calculate in; Choose national grid and fall low and medium voltage distribution network pilot circuit, the Tai Qu with typicalness that decrease the breadboard carrier of distribution Gansu Wuwei electric company and carried out the loss analysis according to the power information acquisition system, pilot line topological data is as shown in Figure 2.

According to line loss is current squaring relation (I ²R) deduction, actual line loss value is not bigger with the line loss value difference that " calculating according to simultaneity effect load " gets.The peak power loss is 17W (0.67%), and a day loss electric weight is 0.034kWh (0.41%); And the peak power loss of active loss reaches 35W, and day line loss amount almost is the former 4 times up to 0.1066kWh (1.3%).

Loss and voltage drop that simultaneity effect load curve and actual no simultaneity effect load curve produce have been contrasted on the single-phase three-wire house lead in.With aforementioned chapters and sections the influence of the simultaneity effect of load curve for house lead in has been discussed; The load and the otherness of load curve shape appear at than on the large group user, and microcommunity user load variations, peak load and the proportion of goods damageds then occur between the simultaneity effect with do not have between two extreme load curves of simultaneity effect.

Table 3 is based on numerical value and the typical percentage error between actual voltage-drop and the loss that the sampling period is the load curve data computation in 1 hour and 15min sampling period.

The numerical value of table 3 load curve data computation and the typical percentage error between actual voltage-drop and the loss

In sum, the present invention is described according to specific exemplary enforcement.It will be conspicuous under not departing from the scope of the present invention, carrying out suitable replacement to one skilled in the art or revise.Exemplary embodiment only is illustrative, rather than to the restriction of scope of the present invention, scope of the present invention is by appended claim definition.

Table 4 is the low meter of the example topology I high confession of a section circuit three-phase and four-line electric energy meter load image data.

The low meter of the high confession of table 4 example topology three-phase and four-line electric energy meter load acquisition tables

Table 5 is an example topology II section circuit massive quantity power supply and measurement three-phase three-wire electric energy meter load image data.

Table 5 example topology massive quantity power supply and measurement three-phase three-wire electric energy meter load acquisition tables

Table 6 is the result of calculation (kW) that the example topology adopts three-phase complete period integration loss algorithm.

Table 6 example topology three-phase complete period integration loss algorithm computation result (kW)

Time	The I section	The II section	The III section	Add up to
					0:00	260.79	114.79	44.63	420.20
0:30	122.07	140.97	44.29	307.33
					1:00	71.44	101.45	45.62	218.51
1:30	48.06	84.54	45.00	177.60

2:00	79.28	124.82	50.09	254.19
					2:30	39.54	130.78	94.12	264.43
3:00	62.23	99.39	45.72	207.35
					3:30	51.68	83.05	45.02	179.75
4:00	47.21	85.20	46.37	178.78
					4:30	53.04	87.46	45.18	185.69
5:00	45.41	81.85	44.82	172.07
					5:30	77.10	113.26	45.20	235.55
6:00	81.12	105.31	44.78	231.21
					6:30	63.98	102.52	46.38	212.89
7:00	293.73	394.06	160.96	848.76
					7:30	452.10	1353.30	896.02	2701.42
8:00	993.42	1308.33	471.64	2773.40
					8:30	1407.49	921.94	81.87	2411.30
9:00	1375.58	1519.98	434.12	3329.68
					9:30	1377.93	5315.56	3870.16	10563.65
10:00	579.38	2359.82	1732.08	4671.27
					10:30	1963.75	4896.77	2843.32	9703.84
11:00	3354.96	7333.64	3693.02	14381.63
					11:30	253.20	3113.11	3182.16	6548.48
12:00	1227.53	2435.90	1357.60	5021.03
					12:30	908.06	1306.79	900.63	3115.49
13:00	2598.77	1519.90	116.15	4234.81
					13:30	189.46	392.94	321.69	904.08
14:00	378.86	918.76	764.55	2062.16
					14:30	157.30	1406.79	1387.59	2951.68
15:00	919.53	529.67	46.84	1496.04
					15:30	147.78	2179.00	2896.87	5223.65
16:00	818.86	782.47	208.12	1809.46
					16:30	1095.98	11189.39	10950.86	23236.23
17:00	3584.01	3492.46	937.05	8013.52
					17:30	390.31	1239.44	984.15	2613.90
18:00	1681.68	21676.94	22592.96	45951.58
					18:30	110.47	1166.50	1232.73	2509.70
19:00	132.96	933.56	836.29	1902.82
					19:30	237.55	914.85	693.87	1846.27
20:00	446.23	374.89	83.63	904.75
					20:30	461.59	2419.19	2023.25	4904.03
21:00	265.14	222.12	54.87	542.13
					21:30	153.34	166.00	53.97	373.31
22:00	117.68	2221.69	2577.59	4916.95
					22:30	76.53	113.19	55.09	244.82
23:00	93.88	176.69	93.33	363.90
					23:30	78.33	1754.06	2078.28	3910.67
Typical case's day total	29426.31	89505.10	71300.52	190231.93

Claims (1)

1. based on the power distribution network theory wire loss appraisal procedure of power information acquisition system, it is characterized in that comprising:

1) draws low and medium voltage distribution network topology data

Following division is done on assessment border according to low and medium voltage distribution network:

(1) medium voltage distribution network

Medium voltage distribution network is pressed trunk and branched line promptly, and electric pressure mainly comprises 10kV, also comprises a spot of 6kV, 35kV and the new 20kV that adopts in some areas;

Topology information: according to circuit model, length, articulate distribution transforming, on-pole switch; Non-full phase equipment separate; If in the test circuit of choosing and the station or the outer circuit in station " handle " arranged, when the back brake of contact, block switch on the post switches, should write down switching time and collection capacity information accordingly;

(2) substation transformer

Back ground Information: distribution transforming model and corresponding copper loss, iron loss, short-circuit voltage number percent, no-load current number percent, reactive compensation capacity configuration; Reactive-load compensation and cut humorous device;

The relation and the calculating of damage value is invested and fallen to reactive power compensator: import the investment of reactive power compensator and fall the damage theoretical value, output investment rationality;

Harmonic treating apparatus investment and fall the relation and the calculating of damage value: the investment of input harmonics controlling device and fall the damage theoretical value, output investment rationality;

(3) the low district's power distribution network of presenting a theatrical performance as the last item on a programme

Low pressure three-phase four-wire system line topological information: according to circuit model, length, load point position and connect separately, each low-voltage circuit is if any operation of phase inversion, should write down switching time and corresponding collection capacity information;

2) import the low and medium voltage distribution network load data

Middle load, the i.e. distribution transformer load of pressing: distribution transforming metering method, mutual inductor ratio, gauging table meter precision.The load metric data: collection period was at least 1 hour, and typical case's day requirement is refined as 15 minutes; The electrical quantity of gathering comprises electric flux, electric power, voltage, electric current, power rate;

Low-voltage load: collection period is 1 hour, and typical case's day typical low-voltage load point is refined as 15 or 1 minutes; The low-voltage load point overwhelming majority is a single-phase load, only needs the single-phase electrical information of record to get final product, if but be multiphase load, like power facilities such as elevators, should write down the three-phase data;

Harmonic distortion: for the bigger load point of load distortion, import the each harmonic data,, can adopt power quality analyzer device measured data to import because general power information acquisition system does not comprise harmonic data;

3) the low and medium voltage distribution network loss is calculated

Employing is calculated based on the exact algorithm of the three-phase complete period integration loss of power information acquisition system:

(1) medium voltage distribution network

The distribution transforming massive quantity power supply and measurement: the collection point is in the high-pressure side, and table is counted three-phase three-wire electric energy meter

${\mathrm{\ΔP}}_{\mathrm{unbalance}}=({I_a}^2+{I_b}^2+{I_c}^2)\·R$

In the formula, Δ P _UnbalancePower attenuation for circuit in the phase three-wire three unbalanced system;

I _a, I _b, I _cBe respectively each phase current of three-phase system;

is respectively the angle of each this phase voltage of phase current hysteresis;

(2) the low district of presenting a theatrical performance as the last item on a programme:

Single-phase family table:

$\mathrm{\Δ}{P}_a={I_a}^2\·R_a+{I_N}^2\·R_N=2{I_a}^2\·R_a$

In the formula, Δ P _aBe single-phase subscriber's line total losses;

I _a, R _aBe this phase circuit phase current and substitutional resistance;

I _N, R _NBe neutral line phase current and substitutional resistance;

The three-phase user:

$\mathrm{\Δ}{P}_{\mathrm{unbalance}}$

$=({I_a}^2+{I_b}^2+{I_c}^2)\·R_p+{I_N}^2\·R_N$

In the formula, Δ P _UnbalanceBe the total loss of circuit in the three-phase four wire system;

I _a, I _b, I _cBe respectively each phase current of three-phase system;

R _pBe three-phase system A, B, C three-phase substitutional resistance;

I _N, R _NBe respectively and be neutral current and substitutional resistance;

Wherein:

${\stackrel{\·}{I}}_N={\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_B+{\stackrel{\·}{I}}_C$

In the formula,

is respectively each phase current of three-phase system;

is respectively the angle of each this phase voltage of phase current hysteresis.

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